Combined work holder and clamp



June 11, 1935. J. FOLK COMBINED WORK HOLDER AND CLAMP Filed July 3, 19307 Sheets-Sheet l June 11, J F K 2,004,602

COMBINED WORK HOLDER AND'CLAMP Filed July 5, 1930 7 Sheets-Sheet 2 June11, 1935.

J. FOLK COMBINED WORK HOLDER AND CLAMP Filed July 3, 1930 7 Sheets-Sheet3 June 11, 1935. J FOLK COMBINED WORK HOLDER AND CLAMP Filed July 3,1930 7 Sheets-Sheet 4 J z 17 M m Q\ WV A07 w 0 00 JM mu I 7 I \M. w 8%Q0 5 m N0 Q. N? m v w MP m h I 0 WI. \\|I| //|I| Qv I IH L I IIIW- I Ifi R w n IHII I III 0 F IIII II I m 1 fifiefibhr 0 0 00 0 0 w 0 /M Q Q%Q0 Mn 0% N% H m %fi g June 11, 1935. 7 J, FO K 2,004,002

' COMBINED WORK HOLDER AND CLAMP Filed July 3, 1930 TSheets-Sheet 5 4144.36 c5 49 45 42 49 J: M 745/30 June 11, 1935. J. FOLK COMBINED WORKHOLDER AND CLAMP Filed July 3, 1930 7 Sheets-Sheet 6 Julrlell,1935. V

. FCLK COMBINED WORK HOLDER AND CLAMP Filed July 3, 1930 7 Sheets-Sheet7 Patented June 11, 1935 UNITED STATES COMBINED woRK HOLDER CLAMP JosephFolk,-La. Porte, Ind., assignor to Slicing Machine Com corporation ofIndian pany, La Portle, Ind., a

Application July 3, .1930, Serial No.-465,59 2

19 Claims. (01. 146-4217) The present invention relates to slicingmachines and particularly to that class of slicing machine in which thesubstance is mounted on a reciprocating carriage and carried past theslicing knife when the carriage is moved. Howaddition I have shown inthis application a modification of that work holder. One object of thisinvention is to provide a novel form of work holder for clamping asubstance on th bottom thereof.

Another object of this invention is to provide a work holder which mayclamp any oneof a plurality of sides of a substance with'equal'effectiveness. H

Another object ofthis invention resides in the provision of a singleoperating means for moving the substance holder past the knife andsimultaneously moving the substance towards the cutting plane of theknife.

Another object of this invention is to provide a substance clamp whichacts also as a substance support.

More specifically an object of this invention is to provide a work clampembodied in a work holder in such a manner that the same acts as a partof the supporting surface of the work holder as well as a clamping meansfor the substance to be sliced, preferably this substance clamp isadapted to occupy a plurality of positions in each of which thesubstance may be clamped firmly thereby. I

A- still further object of this inventionis to provide a work clamp forthe substance being sliced and provide means for moving said clamp toposition the substance in various angular positions on the Work holderin each of which the substance is in operative position to be sliced bythe slicing knife. h V

Other objects of this invention will appear hereinafter as thedescription thereof proceeds.

In the drawings Fig. 1 is an elevational view of a slicing machineembodying my invention; 1 Fig. 2 is an end elevation of the device shownin Fig. 1 and looking from the left in that figurej Fig.3 is a 'viewlooking-in the direction 33 ofFig; 1; 1 V r Fig. 4 is a section takenalong the line 4 4 of Fig.3; v k

Fig. 5 is an enlarged view taken substantially alongthe line 55 of Fig.3;"

Fig. 6 is a fragmentary elevational view showing a modified form of myinvention;

Fig. '1 is a View looking's'ubstantially in the direction'll of Fig. 6showing the work'hol'der in cross-section V in Fig. 8; a v

' Fig. 8 is a section taken substantially" along the line 8'8 of Fig.'7; and J 7 j Fig. 9 is a section'taken substantially along the line 9-9of Fig.8. 4

Referring now more particularly to Figs. 1 to 10" substantially alongline AB 7 4 inclusive, it-will be noted that the slicing machinecomprises a base member lsupported 'by the rubber pads or feet 2.bracket 3 has the upstanding members 4 secured to the base. in' anysuitable mannerand is-adapted to carry a guide ma 5, the upper surfaceof which is shielded by the cover portion 6 of the bracket 3. 4

LA guide bar 1 is secured by means of the screws 8 to the base I and issubstantially square in cross section" as best illustrated in Fig. '2. A

bracket 8 has a bearing portion l0 surrounding the guide rod 5 and hasanother portion engaging the upper surface of the guide bar 'l. Thebracket 9=also-has a plate ll secured thereto by means-of a screw I2 toform with the portion of the bracket 9 which engages the upper sur--face of the guide bar 1, ,a'second guiding means for the bracket 9 and'ameans whereby the turning'movement of the bracket '9 about the guiderod 'fi is prevented. This arrangement permits the'bracket 9 to bereciprocated along the guide rod 5 and the guide bar I ma rectilinearpath.

The bracket 9 is adapted to support the work holder. This work holdercomprises a casting [3 having the integral'bosses' l4 and bolts l5extending through the bracket 9 and into the bosses I 4 for securing thecasting I3 to the bracket 9. r p r A gage plate IB'mounted on a shaft I1is moved longitudinally in the direction of the shaft H by means of anoperatingknob H3. The shaft I l is mountedin a bracket l9 secured to thebase I. The gage plate is provided with a plurality of grooves 20 on oneface thereof. A rotating-knife is driven by a motor 22 in the mannershown in my aforementioned co-pending application orjin any other.suitable manner. A guard 23 protects the rear edge of the 29 on one facethereof. The mechanism so far described inla'f generalway ismorespecifically described in my aforesaid copending application ofthese parts is necessary in this ap'plication as the claims in thisapplication are limited to the work holder and clamp used-for holdingthe substance while it is being "sliced.

I will now proceed to describe the novel form of work holder used forholdingthe substance; in a position to 'be sliced. The casting J3 of.

the work holder has the upper surface-thereof substantially V shaped;vlin'cross-section as best illustrated in Fig. 1, and is covered bygrneans.

of aplate 30'securedthereto by-means ofsuitable bolts 31. As bestillustrated in Fig. 3, there is a largerectangular opening 3| inetheplate 39 and also in the casting [3 for; the reception of the work clamprdesignated generally as 32.

Thecasting l3- also supportsthe guide rods "33-and 34 which extend in adirection substantially perpendicular to the direction of the guide rod5 or in: a direction substantially perpendicular to the cutting plane ofthe knife. A frame 35 has a bearingportion '36 surrounding the guide rod33 and a bearingportion-31 surrounding the guide rod-34onthree sidesthereof. The guide bars 33 and 3 4' -ar e adapted to guide the frame35=in;a rectilinear-path toand from the cutting plane of thexknife. I

' 39- has the arms 43, pivoted thereto: These The frame 35 carries theupstanding lugs,3.8,.

and thesesupport apivot rod 39. This pivot rod arms 43 are secured tothe depending :flange 4! which surrounds the-plate 42 of,-thezwork clamp32., Thedependingflange-4| extends all of'the way round the plate-42:and rotataloly car'- riesthe shafts .43. Gears. securedqto the shafts43 at; one end thereof mesh with each otherso that whenicnje of :theshaftsgis'rotated being rotated in oppqsite directions.

' the others will be rotated also,;.adjacent shafts Each of the shaftscarry a plurality of prongs 45.:A handle 43 on a rod 41 screw threadedinto one of the-shafts 43 and locked in place by a nut 48 is adapted tobe usedfor the purpose of rotating the shaft to which it is secured, andas. a consequence, all of the otherwshafts by'means of the ge'ars 44..When :theshafts 43 are rotated by moving the handle 46 in Fig. 4 in acounterclockwise direction, the prongs 45 will move through the openings45 in the plate 42 so that if a substance is placed on the plate 42, theprongs 'willengage thesubstance and as themovement of. theshaftscontinues, the prongs-will draw the substance against the surfaceof the plate in the manner best described in the patent to .Luschka etal., .No. 1,356,165

patented October 19.1920. 1:

- The frame 35 is provided. with mettle 5o securedthereto by the screws!and by means of this handle the; frame may be ;moved; along theguide'ibars-33 and 34 towards the cutting; planeyof the knife, and atthe-sametime ithe: workfholder maybe moved in. the direction of.

the-guide rod '5 tocarry the .work holder past the slicing knife so 'asto cut' :a.slice..from-the sub-.5

prevent buckling of the slice, and to ention, and it is believed that nofurther descrip' able the operator to cut more uniform slices fromgthesubstance being sliced. This feature there :isstill'a considerableportion of the substance which has to be sliced. In order to do this!provide means whereby the work clamp may belmoved so that the plate 42is inc. vertioaljposition .or in" aJ-position parallel 'to the cutting.planebf the. knife. After being moved.

to'this position; the work clamp operates substantially in they samemanneras. in the aforementioned-patent to Luschka, ,et a1.

The means which I employ to produce the last mentionedresult is asfollows: The clamp 32 as previouslysetforth is pivoted by means of the,arms 4!) to the pivot rod 39. This enables the clamp 42 to be quicklymoved f-rom'a position in the-plane ofthe plate 30 to a position atsubstantially right angles thereto. Along one side of the clampIyarrange the, extension links 52 and 53 pivoted; to each other at54'and to the frame 35 and depending flange 4 l respectively at55:andf5.6. A stop 51 on the link52 isadapted to engage Within the notch58in the link 53 to limit themovernent of the links relatively to?each-other whenlthe work clamp 32 is moved to .thefdotted .line positionshown in. Fig. 4.- Preferably the ,linkswhen in their. extended potheslice being, supported by means of the sup-' portingedge '59 oftheyplate, 30. With this arrangement :practicallyall of the substancemay beslicedasjismor'e clearly, set forth in the patent to .Luschkareferred to above. Obviously the workholderidoes not "have to beV-shaped in cross-section becauserthe clamp will work equallyas'wellwithja work holder having a horizontal supporting surface, or asupportingsurface which extends downwardly towards the cutting plane ofthe knife. Nor does the cutting plane ofthe knifehave to be vertical asillustrated in the drawings. a r

The frame 35 is provided with an adjustable stop 60 screw threaded in aboss 5! and locked in place by. meansgof a look nut 62. This stop BI] isadapted to engage one of the shafts 43 when the clamp 32 isin thepositionshown in Fig. 4. By regulatingthe height of the stop 60,the-position 'of the plate 42 With respect to the plane of the plate .30may beregulated withincertain limits. to thereby position the plate 42-in the best position for clamping the substance. It may be found thatthe clamp will operate better, with the plate 42 either slightly aboveor slightly below the supporting surface of the plate 30, and the stop60 is the means for regulating the amount of this adjustment.

With some substances satisfactory slices may be obtained by slicing thesubstance without regard to the direction in which the fibers of thesubstance extend and in other substances which do not have any fibersthe direction in which the slice is taken is practically immaterial.Therefore, I desire to provide a clamp which may be used to clamp suchsubstancesasit is moved towards the cutting plane of the knife and whilethe clamp is in the plane .of the supporting surface of the work holderand may be so moved as to enable one to position the clamp in a positionparallel to the cutting plane of the knife without the necessity ofre-clamping the substance after the substance has been moved forwardlyas far as possible while the clamp is in the plane of the. supportingsurface of the work holder. In Figs. 6 to 9 inclusive, I have shown sucha work holder and this work holder necessitates only the modification ofthe connection between the work holder and the frame which slides on theguide bars33 and 34. -In this modification the same reference. numeralsrefer to the correspondingv partsin Figs. .1 to' inclusive.

The work clamp is substantially the same as shown in Figs. 1 to 5inclusive, but is attached to the pivot rod in a diiferent manner.:. Tothe depending flange 4|, I secure an angle'bracket 63 by means of screws64. On'the pivot rod 39 are pivoted the arms 65 which carry the inetegral plate 66 having the elongated .slots 6T arranged therein in themanner best illustrated in Fig. 7. Thumb screws68 extend through slots61 and are threaded into the angle brackets 63 as best illustrated inFig. 8. Flanges 69 integral with the thumb screws 38 are adapted to abutagainst the plate 66 adjacent-the edges of the slots 6! so that when thethumb screws are tightened, the plate 66 is held firmly in engagementwith the angle bracket 63 and consequently the clamp 32 must move withthe plate '66 as it moves about the pivot 39 or with the frame 35. Byloosening the thumb screws 68 the clamp 32 may be moved closer to orfarther away from the pivot rod 39 as may be desired, the slots 6'!limiting the amountof permitted movement.

When using this modified form of clamp the parts are normally arrangedin the position shown in Fig. 8 and during the slicing operation theplate 32 is in a position substantially flush with the supporting plate30, the substance being moved towards the cutting plane of the knife thesame as with the embodiment shown in Figs. 1 to 5 inclusive. However,when the frame 35 has reached its extreme left hand position in Fig. 8one may merely release the thumb screws 68 and move the clamp 32 to theright While at the same time holding the frame 35 stationary. Theposition of the clamp 32 will then be as shown in dotted lines at C inFig. 8 and the substance clamped thereon will occupy the position shownin dotted lines at E in Fig. 8. After tightening the thumb screws 68 theWork holder can be swung upwardly about the pivot rod 39 to position theclamp in a vertical plane such as at Dshown in Fig. 8 only at a moreremote position through the link 10.

than shown in Fig. -8 in order that the substance willbe 'clearof theknife.

With the modification of the invention shown in Figs. 7, 8, and 9, it isobvious as with the first form of the invention that the clamp cannot bewith the substance clamped thereon, the clamp would prevent the'pivotII) can then be pivoted to the vertical dotted line position shown inthat figure without reclampingv the substance. Of course,it will beunderstood that in addition to moving the clamp into theverticalposition shown by dotted lines in Fig. 8, the frame whichcarries the clamp is movedtoward the rear of Ithemachine in orderthatthe substance will be moved far enough away from the slicing knifeso as not to abutthereagainst.

In order tohold the clamp in desired position other than a positionwithin the plate 30, I provide a plurality of links 10 and H pivoted toeach I other at 12 and to the frame and clamp respectively at 13 and M.The pivot 12.is a thumb screw having an operating head 15. The stemportion of the thumb screw is screw threaded into a boss 16 on the linkII and passes freely Since the links in and H may be held. rigidly inany angular adjustment relativelyto eachother, it is obvious that theclamp 32 may be held in any position of adjustment within the permittedmovement thereof- Thus if desired slices may be cut from a substancewhile the same is heldat anangle to the cutting plane as well as at anangle to the work holder. 7 V

.It is obvious that the device shown in Figs. 6 to 9 inclusive may beused in the same manner as the device, shown in Fgs. 1 to 5 inclusive,by merely clamping the parts together in the position shownin Fig. 8 andpermitting them to remain in that position. If desired the'links 52 and.53 shown with the modification illustrated in Figs. 1 to 5 inclusive,may be provided with athumb screw in place of the pivot 54. 7 Obviouslythose skilled in the art to which this invention pertains may ,makeother changes in the invention without departing from the spirit thereofor the scope of the appended claims.

Having thus fully described my invention, what I desire to secure byLetters Patent of the United States is: a v 1. In a work support forslicing machines, the combination with a plate having an openingtherein, of a frame slidably mounted in said opening for movementsubstantially parallel to the supporting surface of said plate, and asupporting member mounted on said frame and adapted to occupy a positionin substantially the same plane as said plate, said member beingcombination with a plate having an opening therein; of I a frameislidably .imounted. in said opening for movement'substantially parallel'to' the supportingsurfaceof said (plate, and a supporting. member.mounted ;onI-1 said frame and adapted to occupy a'position in:substantially the same plane assaid plate,i'said member being alsomovably mounted on saidxframe for'movee ment to a position at an angleto said plate, and meansizfor clampinga. substance against said memberwhile said member is in either of said positions, said mounting for saidmember being such that: the substance" may remain clamped thereonwhile-the member is being moved from .one position to the other.

3; A substance clamp for slicing machines comprising a trough having twoflat angularly disposedsupporting r'nemberaone of said members having anopening therein,--guides'arranged insaid opening, a frame 'slidableonsaidguides, a plate pivoted to said'frame so' as to be m'ovable fro'maposition substantially parallel with said last mentioned member and to aposition at anangle thereto, andlclamping means cooperating withsaidplatefor holding a substance thereon; E w

4. A work holder for slicing machines cornprising a plate having anopening therein, a frame guided for movement in" said opening, a clampextensibly' and pivotally mounted on said frame, and means for holdingsaid clamp-in various angular positions about'its pivot so astopresent adifferent portion of a substance being sliced in a position 'to'besliced .without "reclamping the substance.

5. A work holder for opening therein, a frame guidedfor-.,movement insaid elongated opening,"abr'acket pivoted to said frame, a clampadjustably mounted on said lar movementwith respect to said worksupport,

' the substance means for holding 'saidclamp in various angu-.

lar positions relative to the supporting surface of said work"suppo'rtincluding a-position in which the substance engaging portion thereof isparallel with the'surface of said support and substantially coincidentaltherewith, and means for guiding said work support while the sub-'stance is being sliced, said meansfor moving said clamp being operableindependently of the direction of feed of saidj-wor'ksupport so-that theportion of the substance which is clamped may be varied withoutchanging-the direction of feed of said-work support, and saidclampcooperating solely with the "adjacent to hold the same firmly againstthe clamp.

"'L-In a holder for slicing machines and the like, the combinationwith-a member having an opening, therein, surrounded by a substantiallyflat supporting surface for supporting the substance to be sliced, aclamp arranged Within said opening and movable'ftherein to feeda'substance along said supporting surface, said'clamp slicing machinessome, prising a supporting plate having an elQngated said clamp havingsurface of having asurface-sagainst which the substance to be slicediisclamped," and retractable means movable .intoliand out of a positionabove said surface onsaid clamp for holding the substance against.saidxsurface' of' said clamp when desired, said retractable. meansbeingmovable to an inoperative-position so as not to obstruct said surface ofsaid clamp whereby said surface on said clamp and; said supportingsurfaceform a combined substance supporting surface on which thesubstance may be supported independently of the same being clamped andfor'manual feedingiof the substance along said surfaces. 8. A workholder .for slicing machines comprising a substance supporting member, apivotally mounted substance supporting member having the surface thereofin a plane substantially flush with thesupporting surface of said firstmember and formi'ng a combinedsurface upon which the substance may besupported and fedimanually relatively-toward a slicing position, saidmembers being also movable relative to each other duringthe feedingmovement while maintaining said surfaces thereof substantially; flush.with-each other, and-retractable substance.engagingprongs on thepivotallyimounted memberfor engaging the adjacent portion -of thesubstance" and arranged when in operative position to hold the samepositively against said last mentioned member and thus maintain a fixedrelation. between said last mentioned member andthe substance while saidmembersare moved relative to each other or when I the pivotally 'mountedmember is shiftedonitspivot. j- I 9; Aworkholde'r for slicing machinescomprising" a I substance supporting. member, a

second substance supporting memberhaving the surface. thereof .in 'aplane substantially flush with the. supporting surface of said firstmem-. ber and forming a combined surface upon which the substancemaybesupportedand fed manually relatively toward a slicing position,said members being; also movable relative to each other duringthefeeding movement while maintaining said surfacesthereofsubstantially'flush with each othenj.andretractable substance engagingprO igS- on said secondsubstance supporting member for engaging theadjacent portion of the substance and arranged when .in operativeposition to hold the same positively against said last, mentioned memberand thus maintain a. fixed relation between said last mentionedmemberand the substance whilesaid members are moved relative toeachother, said retractableisubstance engaging prongs being constructedto engage andv hold the substance againstjlateral shifting movementrelative to said memberand also prevent movement of the substance awayfromsaid member;

'10; A work holder for slicing machines .comprising a substancesupporting member, a second substance supporting 'member having thesurface thereof in the same plane as'the supporting surface of saidfirst member and forming abombined' surface, uponjwhic'h the substance'm'ay beisupported and fed manually relatively toward a slicingposition, said members beingalso movable relative to' each other duringthe feeding movement while 'maintaining said surfaces thereof in thesame plane, and substanc'e engaging prongs on one of saidmembersfor'-engaging=the adjacent portion of the substance and arranged whenin-operative position to hold the same positively against said lastmentioned member and thus'maintain a fixed relation between saidlastmentioned member and the substance while said members are movedrelative to each other, said second sub stance member being -pivotallymounted and adapted toswingthrough various vertical angular positions.

11. In a slicing machine, a work holder for supporting and holding asubstance while the same is being sliced, comprising a substancesupporting plate having an opening therein with supporting surfacesthereon surrounding said opening on more than one side thereof, a secondsupporting plate arranged within said opening and having the supportingsurface thereof substantially flush with the surface of said firstplate, clamping means on said second plate for holding a substancepositively against said second plate by engagement with the adjacentportion only of said substance, and means for moving said second platein said opening in a direction toward the cutting plane of said knifewhile the surfaces are maintained flush with each other, said secondsupporting plate being pivoted about axes parallel to the plane of thefirst plate and being arranged and mounted so that it may be swung fromsaid plane to assume various angles with respect thereto toward thecutting plane of the slicing machine.

12. A work holder for slicing machines comprising a supporting frameslidable in a direction toward a cutting position, a clamp mounted formovement on said frame to various angular positions with respectthereto, means for holding a substance firmly against a surface of saidclamp against shifting movement in any direction relative thereto, meansfor holding said clamp in various angular positions to which the samemay be moved comprising an extensible link operable in any desiredposition of adjustment of said clamp, and'means for guiding thesubstance clamp bodily always in the same direction independently of theangular position to which the clamp is moved.

13. In a work support for slicing machines, the combination with a platehaving an opening therein, a supporting member slidably mounted withinsaid opening without changing the angular position thereof with respectto said plate and having the supporting surface thereof in substantiallythe same plane as said plate, said member being also movably mounted toposition the supporting surface thereof at an angle to said plate, andmeans for clamping a substance against said member while said member isin either of said positions.

14. A substance clamp for slicing machines comprising a trough, havingtwo flat angularly disposed supporting members, one of said membershaving an opening therein, a plate selectively pivotally or slidablymounted within said opening and movable from a position substantiallyflush with the supporting surface of said last mentioned member to aposition at an angle thereto, and clamping means cooperating with saidplate for holding a substance thereon, said plate being slidable towarda slicing position in any of its angular positions of adjustment withoutchanging its angular position of adjustment relative to its supportingsurface.

15. A substance clamp for slicing machines comprising a trough havingtwo fiat angularly disposed supporting members, one of said membershaving an opening therein, guides arranged,

I 5 m1 said pening" substantially parallel to said firstmentionedmember, a frame slidable'on s'aid guides, a plate pivoted tosaid frame so as to be movable from a positionsubstantiallyparallel withsaid last mentionedT memberend to a po- 'sition at ananglefthereto iandmeans cooperating with said plate i'n'either "of said positions forholding a substance against thesame in position to be fed toward theposition at which the slices are formedand for preventing relativemovement of the substance andpl'ate parallel to the supporting surfaceof said plate.

16. In a work holder for slicing. machines,

the combination with a supporting plate, of an, auxiliary platesubstantially parallel with said permit said auxiliary plate to beadjusted to various positions relative to said pivot, means for holdingsaid auxiliary plate and pivot in adjusted position with respect to eachother, and means for holding said auxiliary plate in any of its adjustedpositions about said pivot.

17. In a work holder for slicing machines, the combination with asupporting plate, of an auxiliary plate substantially parallel with saidfirst mentioned plate, said first mentioned plate having an openingtherein in which said auxiliary plate is movably mounted, a pivot forsaid auxiliary plate about which said auxiliary plate moves, saidauxiliary plate and pivot being bodily movable in unison with each otherrelative to said first plate, an extensible connection between saidpivot and said auxiliary plate to permit said auxiliary plate to beadjusted to various positions relative to said pivot, means for holdingsaid auxiliary plate and pivot in adjusted position with respect to eachother, and means for holding said auxiliary plate in any of its adjustedpositions about said pivot, com prising a pair of links pivoted to eachother and pivoted respectively to said auxiliary plate and to said firstmentioned plate, and means associated with the common pivot for saidlinks for holding said links in adjusted angular position with respectto each other.

18. In a slicing machine, the combination with a slicing knife, of awork support movable rela-, tive to said slicing knife having asubstance suppotring surface with an opening therein, a hear-- ingmember slidable beneath the supporting surface and slidably guided byguides on said support for movement in a direction substantiallyparallel with said supporting surface, a substance clamp pivotallymounted on said bearing member and having a substance engaging surfaceagainst which the substance is to be clamped adapted to lie either in aplane substantially 'coincidental with the plane of the supportingsurface when said clamp is in one position, of adjustment, or in a planeat an angle thereto when the clamp is in another position of adjustmentabout its pivot, and means for holding a substance to be sliced firmlyagainst said substance engaging surface of said clamp.

19. In a work support for slicing machines, the combination with a platehaving an opening therein of a frame slidably mounted in said openingparallel withgsaid p1ate, and a supporte ing member mounted on; saidaframe for sliding movement therewith and: adapted to occupya positionin substantially the same plane assaid plate, said.- supporting memberbeingalso pivotal- 1y mounted; onsaiclframe toa. position substantiallyperpendicular thereto; means forholding

